1. Technology Field
The present invention generally relates to a storage system, and a controller and an access method thereof, and more particularly, to a storage system having multiple non-volatile memories, and a controller and an access method thereof. The present invention is adapted for performing a multi-channel access for multiple non-volatile memory chips and performing a single channel access for a single non-volatile memory chip with less enabling signal pins.
2. Description of Related Art
With a quick development of digital camera, cell phone camera and MP3, demand of storage media by customers is increased greatly. Since a flash memory has the advantages of non-volatile, energy saving, small size and none mechanical structure etc., it is suitable for portable applications, and especially for portable battery-powered products. A memory card is storage device applying the flash memory. Since the memory card has a small sized and is easy to be carried around, it is widely used for storing important personal data. Therefore, the flash memory industry becomes a hot industry within the electronics industry recently.
To increasing a data accessing amount, a non-volatile memory module (for example, a flash memory module) of a general storage system is formed by stacking and packaging a plurality of memory chips, and the memory chips can be interleavely accessed, so that the data accessing amount within unit time is greater than that of an earlier memory module only packaged with a single memory chip.
FIG. 1 is a schematic block diagram illustrating a flash memory storage system according to the conventional technology. Referring to FIG. 1, a flash memory system 100 includes a controller 102 respectively controlling a first chip enable pin CE0, a second chip enable pin CE1, a third chip enable pin CE2, and a fourth chip enabling chip pin CE3 for enabling a first flash memory chip 104, a second flash memory chip 106, a third flash memory chip 108, and a fourth flash memory chip 110. The flash memory system 100 further includes a control bus 112 electrically connected between the controller 102, the first flash memory chip 104, the second flash memory chip 106, the third flash memory chip 108, and the fourth flash memory chip 110 for transmitting instructions. The flash memory system 100 further includes a first I/O bus 114 electrically connected between the controller 102, the first flash memory chip 104, and the third flash memory chip 108 for transmitting data, and a second I/O bus 116 electrically connected between the controller 102, the second flash memory chip 106 and the fourth flash memory chip 110 for transmitting data.
In such the flash memory chip system 100, for example when the controller 102 intends to write data into the first flash memory chip 104, the controller 102 enables the first memory chip 104 via the first chip enable pine CE0, and the first I/O bus 114 transmits the written data. When the controller 102 intends to simultaneously write data into the first flash memory chip 104 and the second flash memory chip 106, the controller enables the first flash memory chip 104 via the first chip enable pin CE0 and enables the second flash memory chip 106 via the second chip enable pin CE1, and then transmits a writing instruction to the first flash memory chip 104 and the second flash memory chip 106 by the control bus 112, and then simultaneously transmits the written data via the first I/O bus 114 and the second I/O bus 116.
According to the foregoing configuration, the conventional non-volatile memory storage system is capable of enabling a plurality of non-volatile memory chips by a plurality of chip enable pins, respectively, so as for performing a single channel access to a specific non-volatile memory chip, and meanwhile the conventional non-volatile memory storage system is also capable of performing a multi-channel access to the multiple non-volatile memory chips via a plurality of I/O buses after respectively enabling the non-volatile memory chips.
Although the conventional technology is capable of performing the single channel access or the multi-channel access to the non-volatile memory chips, this technology requires for a plurality of chip enable pins for respectively enabling multiple non-volatile memory chips, which inevitably increases the size of the non-volatile memory storage system. This is a large disadvantage for those portable memory cards which desire a small overall size. Moreover, applying of multiple chip enable pins can also increase a cost of the non-volatile memory storage system.